Combined electric switch and fuse



July 3, 1923. 1,460,914

J. G. LUNDGREN COMBINED ELECTRIC SWITCH AND FUSE Filed Jan. 26, 1921 2Sheets-Sheet 1 (fa/M5 6. Zufldyrm,

: 'JuIy' '3, 1923.

- J. G. LUNDGREN COMBINED ELECTRIC SWITCH AND FUSE 1921 2 Sheets-Sheet 2Filed Jan. 26

:u a I Patented July 3, 1923..

UNITED STATES JONAS G. LUNDGEEN, OF CLEAR LAKE, 101 3 11.

COMBINED ELEG'IRIC FEWIZ'GH JZ-NND FUSE.

Application filed January 26,

1 0 all whom it may concern:

Be it known that 1, Jones Gosriir Lonn- GREN, citizen of the UnitedStates, residing at Clear Lake, in the county of Gerro Gordo and Stateof Iowa, have invented new and useful Improvements in Combined ElectricSwitches and Fuses, of which the following is a specification.

My invention relates to a combined fuse and switch construction.

In many electrical installations the fuse exposed to view with theresult that when thefusible element has burned out there is atemptation, which is frequently yield d to especially if there is nosupply of the proper fusible elements on hand, to put a copper wire orsome like form of conductor in the place of the fuse. This procedure, asis well known to those skilled in the art to which this inventionappertains, frequently leads to serious trouble which would not occur ifthe fusible element had been in place and capable of performing itsfunction. Furthermore, the service switch .irequent ly placed in exposedplaces where children or unauthorized persons may come in contact withthe terminals with resulting serious consequences.

This invention aims to avoid these and other difiiculties and also toprovide a coinpact arrangement whereby the fuse and switch are combinedin a unitary structure wherein the fuse is not exposed to view andwherein the terminals of the switch are also concealed.

This invention also aims to provide a fuse construction which may bereadily assembled and disassembled for inspecting or replacing thefusible element.

Another object of my invention is to provide a combined fuse andswitch-block so arranged that the conductors may be firmly and readilyconnected thereto.

Other objects of the invention which consist in novel features ofconstruction and rangements of parts whereby a compact and economicalstructure is obtained, will be-- come apparent on reference to thefollowing specification which describes the invention in connection withthe accompanying drawings.

In the drawings Figure 1 is a plan View of one form of my inventionshowing a plurality of terminals disposed on a switch-block.

Figure 2 is a central sectional view Figure is a perspective viewshowing the parts comprisin the detachable cap and screw of the switchmechanism in separated position.

Figure (3 is a plan View of another form of my invention showing theswitch elements pivotally connected.

Figure 7 is a central longitudinal section through one of the switchelements.

Figure 8 is an end view of the switch in closed position showing one ofthe switch elements in section on the line 88 of Fi ure 7. c

Figure 9 is a vertical section through one at the terminal connectionsto the switchbloclr. the section being taken on the line 9-4) of Figure7.

Heifer-ring to the form of the invention ill trated in Figures ii to 5,the numeral 10 desig toe the switch-block which is preferably l'substantially rectangular shape and formed of some insulatingmaterialsuch as porcelain or balrelite. This block is torn x, with transversegrooves which are ad: .icd to receive the insulated conductors 12. Thesegrooves are intersected near opposite sides of the block by slots 13, inwhich are located the switch blades consisting of flat elongated baseportions is: disposed in the bottom of the slots and secured to theblock by means of suitable screws or other fastening devices (notshown). Upstandinefrom the bases are the blades 15 which are adapted tocooperate with the spring lingers of the detachable switch and fusemechanism. Each base portion lei is extended into a groove 11 and isprovided with apertures and screw threads which apertures are spacedapart suflicient disbare wire to pass thcrethrough, so that at thispoint the insulation is cut away :lirom the wire, and a metallic plate16 of proper dimension having suitably quaced apertures is used to clampthe wire position and make good electrical "herewith and for thispurpose the are passed through the apertures of the plate 16 and engagethe threaded apertures of the plate 141-. Recesses 20 are formed neareach corner of the block and in axial alignment with the slots 13. Meansare provided in each of the recesses for electrically connecting theterminals of an electrical conductor to a terminal of the switch blockand this means comprises a metallic plate 21 located in the base of eachrecess and properly secured to the block 10 and another metallic platebetween which plates the uninsulated portion 23 of the conductor isinserted, the irsula ion shown at 2 1 being received through a verticalslot of proper dimension formed in the switch block.

The base-plate 21 is provided with apertures and screw threads and theupper plate 22 has suitable apertures for receiving the screws 25whereby the two plates may firmly bind the uninsulated portion of theconductor between them. 11. blade 26 is attached to or formed integralwith the upper plate 22 and is adapted to cooperate with the springlingers 33 of a detachable combined switch and fuse d "cc as willhereinafter appear. its show. in, Figure 1, there are four switch blades26 arrant d near the corners of the rectangular SWlLCllblock and twoswitch blades 15 which le ter are connected with the transverselyextending conductors 12. p

The combined fuse and switch devices are provided so that pairs of theseblades 15 and 26 may be variously connected in ac cordanee withconditions. These combined switch and fuse mechanisi'ns are designatedas a whole by the numeral 80 and each consists of a cylindrical, hollowcasing 310i insulating material in each end of "which is inserted orembedded a threaded metallic bushing 32 and this bushing is providedwith spring fingers 83 adapted to engage and make contact with theswitch blades l5 and 26 in the usual manner. may be attached to thecasing in any suit able manner. The outer end of each pin or rivetprojects into an opening formed in the casing and this opening issubsequently filled by a plug 29 of wood, wax, putty or the like so thatthe outer surface of the easing is continuous and of even contour, asshown in Figure 2.

The fuse is of novel construction in order that the same may be readilydisassenv bled and assembled, and for this purpose a cylindrical fusebody 3-1 of insulating material and of such dimension as to be capableof fitting within the hollow casing 31, is provided. The fuse body isformed with central bore 36 and with rece sed ends 37 in The bushingjoint adaptediio connect the cap to the fuse body. It w l be noted thatin Figure 4: the

upper surf e of the groove 16 is shown as 12 'ovided with a slight taperindicated at 4?! so that the cap may be pressed into firm electricalcontact with the corresponding end 4h) of the fuse 11. However, it willbe noted that a strai ht surface may also be used in connection with thegroove 46 of the T. yonet joint since the screw-plugs 18, hereinafterdescribed, will force the caps 41 mly into contact with the flatportions -10 the fusible element. The fuse body shown 1' l is adapted tobe inserted within block or casing 31 and the metallic -?eof extendwithin the threaded portions of the bushings 32. In order to 1' "wecertain of good electrical connections between the bushings 32 and thefuse, a nut r screw-plug 4-8 of metallic material, such bras s providedwith threads for enlugthe threads of each bushing 32 and erting thesescrew-plugs in the opposite ends of the casing 31, the fuse is firmlyheld therebetween. Each screw 18 is also provieed with a centralthreaded aperture l9 and with a kerf 50 adapted to engage a row-driverwhereby the plug 49 may be easily detached. For the purpose ofconcealing the conducting parts of the apparatus and pre'venti gaccidental contact therew ith, a cap 51 of non-conducting material isformed with a slotted boss 52, the slot of which is adapted to engagethe head of a T-shaped element 53 having a threaded stem 51 adapted toengage the threads 4-9 of the screwplug. The T-shaped element isprovided with an aperture 37 which is adapted to align with an aperture56 passing transversely through the hub 52, whereby a removable pin orwire may be inserted for retaining the cap 51 and the T-shaped elementin assembled relation. By removing the pin from the apertures and 56 andplacing the stem in the central aperture 54 of the cap 51. the T-sl-aped element will be positioned for engaging the kerf 50, and therebyfunctioning as a screw-driver with relation to the plug 48, or theT-shaped element may be used as a screw-driver independently of the cap51.

In assembling the detachable switch and fuse mechanism, the assembledfuse is inted within the casing 31, screw plugs 48 are applied and thecaps 51 are secured to these plugs, whereby the device presents aneatappearance and exposes only the insulating material of the casing 31 andcaps 51 to view, with the exception of the switch blades 33, whichextend downwardly through slots in the casing. As said before, thesecombined switch and fuse devices connect the switch blades 15 and 26,and since the latter are located in slots in the switch block 10 and theblock is provided with cylindrical depressions 57 of substantially thesame or slightly larger diameter than the casings 31 it will be apparentthat when the switch devices are applied in closed position that theconducting terminals are protected from accidental contact therewith byi-L'PGl'SOD not acquainted with the construct-ion of the switchmechanism and that anyone accidentally coming into contact therewith isin little danger of being subjected to an electrical shock.

In case the fuse is burnt out, or is de c tive, or in order to inspect;remove the cap 51, the plug 48 and shake out the fuse lody 34:, the capsl1 can then be readily de y and the disks 38 removed. l nder theseconditions the interior of the switch block is exposed to view, as wellas the fuse element and if it is desired to put another fuse element inplace it is only necessary to i rt the same through the apertures cf thedisks 38, after removing the spent fuse as above described. The switchblock 10 is provided with openings 58 for receiving suitable means forfastening the switch mechanism to a wall or switch board slab.

Another form of my invention illustrated in Figures 6 to 9, differs fromthe form just described chiefly in having the switch members pivotallymounted instead of completely removable and this form is primarilyintended for a main or service switcl. The switch mechanism is mountedupon a block 60 having two forward recesses 61 and two rear recesses 62formed therein. In each of the rear recesses 62 a base plate 63 isplaced, see Figure 9, on which is mounted a bent plate 65 having anupstanding blade portion 66 to which the hollow cylindrical casing 67 ofthe movable switch member is pivotally connected in a manner hereinafterdescribed. The rear end of each casing 67 is closed by a metallic plug68 having spaced fingers 69 extending therefrom for embracing theupstanding blade 66 of the bent plate 65. A pin 70 is passed throughaligning apertures formed in the blade 66 and vlingers 69, this pinbeing retained in position by suitable retainers such as washers 71 andthe riveted ends of the pin 70 which prevent lateral movement of thewashers. It vill be understood that other retaining means such as cotterpins or screws and nuts or the like may be used instead of the meansherein employed. In order to allow pivotal movement of the casings 67about the blades 66 said casings are provided with vertical slots 72which provide clearance for the blades 66 during pivotal movements ofthe casings.

In the forward recesses 61 a base plate 75 is inserted and upon thisplate is placed an elongated plate 76. The plate 75 is provided with acurved portion 77 which is produced upwardly into the vertical blade 78.The plates 75 and 76 are secured to the switch blocl; 60 by suitablefastening devices (not shown) and the plate '75 is provided withapertures adapted to align with suitable apertures formed in a plate 80which engages over the uninsulated portion of the wire 81 for tightlyclamping the wire into electrical contact with the plate 76 and for thispurpose screws 82 are inserted through the aligning apertures and theplate is pressed downwardly until the wire is tightly clamped betweenthe plate 80 and the plate 76.. The wires 83 leading into the rearrecesses are secured in place in similar main ner by means of the uppercontact plate which is provided wit-h apertures through which screws 85are inserted for the purpose of e: L lging threaded apertures in theplate 63, suitable openings being made in the block 60 to allow thescrews to be tightei'ied.

Each hollow cylindrical casing 67 is closed at one end by the metallicplug 68. and a fuse 66, similar in construction to the fuse described inconnection with the first form of my invention inser ed within each inguntil the metallic cap 87 of one end of the fuse is received within andcontacts with the shell of the plug 68. The cap 87 at the other end ofthe fuse body is received within a threaded bushing 32 having depeiulingspaced lingers 33 for engaging the blade 78 of the forward tern'iii'ialsof the switch mechanism. It screw plug 48 screws into the bushing s2 andcontacts with the corresponding metallic cap 87. A cap 51. of insulatingmaterial is provided with a thread ed stem 54/ adapted to engage acentral threaded aperture in the screw plug 48'. The primed numeralsrepresent parts corresponding in construction and function to the partsdesignated by the corresponding cardinal numerals in the description ofFigures 1 to 5. i

The two cylindrical casings 67 are connected together at the forward endby a bridge piece 90 having inwardly projecting ribs 91 secured to thecasings. The bridge piece 90 is provided with a circular opening 92whereby the movable switch members including the casings 67 may bereadily manipulated to open or closed position.

hen the switch is in closed position current coming through conductors81 is transmitted by means of spring finger 33 to threaded bushings 32',from thence to tor S3.

screw plug l8, cap 87 through the fusible element 39, which issubstantially the same in each form of the invention herein described,to the rear cap 87, through shell 68, lingers 69, to blade 66 and thento conduc- It is evident that the blowing of the fuse will break thisline of conductors and the fuse may be replaced by swinging the casingsto open position, taking out the removable parts 51, 48, 87 and the fuseas described in connection with the correspond ing parts of the iii-stform of the invention, inserting the new fuse and assembling the partsin reverse order.

'il he cylindrical openings at the rear of the casings surrounding thespring lingers 69 are closed by means of plugs 88 of insulating materialwhich conform exteriorly to the contour of the casings and except forthe continuation of the slots 72 completely conceal the switch blades 66and spring fingers 69.

The block is also formed with curved longitudinal depressions 89 adaptedto receive the lower portions of the casings when the latter are closedand thus conceal the conducting portions of the switch mechanism in ahousing of insulating material It will be understood that the particularconstructions described and shown have been chosen for illustrativepurposes merely and that the invention as defined by the claims hereuntoappended, may be otherwise embodied and applied without departing fromthe spirit and scope thereof.

Having described my invention what 1 claim and desire to secure byLetters Patent, is

1. In an electrical switch, the combination of a switch block havingspaced terminals, a casing carrying contacts adapted to make electricalconnections with said terminals, a fuse in said casing connecting saidcontacts, said block having recesses in which said terminals are locatedand grooves therein in which portions of said casings are adapted tolit, and detachable means for closing an end of said casing whereby whenthe switch is closed all oi the conducting parts thcreoi are concealedfrom view.

2. An electrical switch having in combination a movable memberconsisting oi a h0llow casing, spaced contacts in said casings and iuseccmpris lig a hollow body, metallic caps detachably connected to saidbody, a luse clement electrically connecting r: c; and Lt removable plugengaging one of id contacts i'or 'Lorcing sail contacts. caps and fuseelement into firm eleccontact.

5. in an electric switch the combination oi a lixcd block of insulatingmaterial having recesses form-ed therein, terminals located in said acasing of insulating material hinting c 'acts projecting therefromadapted [O engage said terminals, a time within the casing electricallyconnectsaid contacts, said block having grooves in alignment with saidrcrece \ing said casing when the latn operative position, whereby thecoerminals and contacts are completely said block and casing.

l. in clcctr i switch including a member collelSlI-llllf oi a hollowcasing of insulatiip' material having spaced contacts, a fuse within thecasi z a removable metallic plug engaging one oi said contacts lf'ormaking lirm electrical connections between said con tacts and fuse, acap of i'ioincoinlucting material adapted to act as insulator for saidplug, and a disassembling tool detachably connecting said cap and plug.

in testimony whereof l have hereunto set my hand in presence of twosubscribing witnesses.

JONAS G. LUNDGREN. Witnesses Gnonen KNULsoN, FRED OPEL.

